Leicester C. Hemingway, a writer and only brother of the late American novelist and Nobel laureate Ernest Hemingway, died Monday of a self-inflicted head wound caused by a borrowed handgun at his home in Miami Beach, according to the police. His family reported that he suffered from diabetes and had been depressed after undergoing five operations in recent months. He was 67 years old.

In 1961, Ernest Hemingway killed himself with a shotgun in Ketchum, Idaho, at the age of 62. Their father, Dr. Clarence Edmonds Hemingway, also shot himself during a period of depression, at his home in Oak Park, Ill., in 1928.

Leicester Hemingway was a writer whose six books included novels and a biography, ''My Brother, Ernest Hemingway.'' For the last five years he had published a small monthly newsletter on fishing, The Bimini Out Islands News. He frequently wrote about fishing and outdoors activities for men's publications.

All his life, Leicester, who was 16 years younger than Ernest, had lived in the shadow of his famous brother. When his first novel, ''The Sound of the Trumpet,'' based on his war experiences in France and Germany during World War II, came out in 1953, it was received with slight praise.

Reviewing the novel in The New York Times, Charles Poore wrote, ''Leicester Hemingway belongs to the first younger generation shaped by the books of Ernest Hemingway.''

On the eve of World War II, Leicester revealed in a widely reprinted article that Nazi submarines were using fueling bases in the Caribbean area.

In the biography of his brother, Leicester wrote, ''Ernest came straight out of the Midwestern Victorian era of the 90's.'' Ernest called his brother Duke. In recent years, Leicester had grown a beard and, according to Andy Taylor, a family friend, ''When he walked down the street he looked the spitting image of his brother.''

Mr. Hemingway was born in the Chicago suburb of Oak Park. He is survived by his wife, Doris; two daughters, Anne Feuer and Hilary Hemingway; two sons from a previous marriage, Peter of Regina, Saskachewan, and Jake of Silver Springs, Md.; two sisters, Sunny Miller and Carol Godner, and seven grandchildren.